Cleaning scrapers for twin cylinder stencil duplicators



H. J. PICKING July 13, 1965 CLEANING SCRAPERS FOR 'I 'WIN CYLINDERSTENCIL DUPLICATORS Filed July 8, 1965 S w mw uh A C 11H n M y 53 V/ V wH United States Patent CLEANING SCRAERS F911 TWIN CYLINDER STENCHLDUPLHCATGRS Henry John Picking, Tottenham, London, England, as-

Signor to Gestetner Limited, London, England, a Britrsh company FiledJuly 8, 1963, Ser. No. 293,523 Claims priority, application GreatBritain, July 11, 1962,

1 Claim. (Cl. 101-425) This invention concerns improvements in orrelating to duplicators, and more particularly twin cylinder stencilduplicators, i.e. duplicators in which the stencil is adapted to. befitted over an ink screen mounted around two printing cylindersrotatable about parallel axes and positioned one above the other.

it is .at times, for example when duplicating is required to be carriedout with ink of a different colour from that last used, necessary forthe old ink to be cleaned from the two printing cylinders. An existingapparatus used to ole-an the cylinders comprises a frame which carriesan elongated rectangular cleaning card and which is, after removal or"the ink screen and inking rollers, adapted to be clipped into the spacebetween the printing cylinders so that the card extends with itsdirection of length parallel to the cylinder axes and with its planeparallel to the plane passing through such axes, so that the upper edgeof the card engages the periphery of the upper cylinder, whilst thelower edge of the card engages the periphery of the lower cylinder.Cleaning is effected by applying such apparatus to the cylinders andthen rotating the latter thereby causing the ink to be scraped from thecylinders onto the edges of the card.

Such apparatus suffers from the disadvantage that it requiresconsiderable etlcrt on the part of the operator to turn the cylinderagainst the force provided by the card and that, when the cylinders arestopped and the apparatus removed, lines of ink deposit remain on thecylinders along the line of contact therewith of the edges of the card,particularly the lower card edge.

1 t is an object of this invention to provide an improved cleaningapparatus for twin cylinder stencil duplicators.

The apparatus of this invention comprises a holder adapted, in use ofthe apparatus, to receive a card or cards in such a position that thecard or cards have two cleaning edge portions which can be appliedagainst the two cylinders so that such edge portions are in contact withthe cylinders, one with each cylinder, the cleaning edge portionsprojecting from the holder at angles of less than 90 to a plane which isparallel to the plane through the cylinder axes, such angles beingmeasured in the same direction in such plane. Generally, in use, aduplicator stands on a horizontal surface and the plane through thecylinder axes is Vertical. Thus, when apparatus according to thisinvention is applied to such a duplicator, each of the said cleaningedge portions will project at an angle of less than 90 to the verticaland they will both be generally directed upwardly or downwardly.

it will be appreciated that both cylinders of a twin cylinder duplicatorrotate in the same rotational direction. When using the apparatus ofthis invention, the cylinders would be rotated in the diretcion whichwould cause each cleaning edge to have a shaving action on the cylinderwhich it engages. The known apparatus previously men tioned, because oneedge portion of the cleaning card projects upwardly and the oppositeedge portion projects downwardly, has one edge portion shaving itscylinder and the other edge portion riding over its cylinder whateverthe direotion of rotation of the two cylinders. The apparatus of thisinvention gives better and more uniform cleaning results.

3,ld4,l5fi Patented July 13, 1955 ice Preferably, the edge portions arearranged to extend upwardly in use of the apparatus so that ink scrapedfrom the cylinders will tend to run onto the card, rather than drip orfall therefrom, as might occur if the edge portions extended downwardly.The edge portions may conveniently be arranged so that each makes thesame angle with the tangent to the appropriate cylinder at the point ofcontact of the edge portion with the latter. A suitable value for suchangle is between 20 and 30.

Although the holder could be adapted to receive a single wide cardretain the latter in such a bent form that the upper and lower edges ofthe card project from the holder at the appropriate angles,advantageously the holder is adapted to receive and retain two narrowstrips of card with longitudinal edges of such strips projecting fromthe holder at the appropriate angles. Conveniently the holder isprovided with two spaced strip-receiving slots arranged at theappropriate angles.

Preferably, according to a further feature of the invention, the card orcards, when mounted in the holder, project outwardly from one sidethereof for easy removal of the card or cards without the necessity oftouching the inky edges thereof.

Conveniently the holder may comprise a body having the said edgesprojecting from its upper and lower sides and having between such edgesa hollow space serving as a ma azine or container for unused cards orstrips.

Although the holder could be of a form adapted simply to be held in thehand and pressed between the cylinders so that the card edges arepressed onto the cylinders, preferably the holder is adapted to bemountable on the duplicator itself for accurate positioning of thecleaning edges relatively to cylinders. y

In a convenient construction, the holder is pivotably mountable on theduplicator, for example by the body of the holder being carried on twotransversely spaced arms projecting outwardly from a shaft adapted to bemounted at its ends removably in journals in the side frames of theduplicator between which the cylinders are mounted.

Instead of requiring to be pressed manually against the cylinders, theapparatus could be bi-assed, e.g. spring biassed, towards the cylindersto maintain the edges against the latter.

In order that the invention may more readily be understood the followingdescription is given by way of example, reference being made to theaccompanying drawings, in which:

FIGURE 1 is a front elevation'of one embodiment of cleaning apparatusaccording to the present invention; and

FIGURE 2 is a cross-section on the line 11-41 of FIG" URE 1, to anenlarged scale, and shown in the operative position, adjacent portionsof the twin cylinders of a rotary duplicator.

Referring now to the drawings, the apparatus of the present inventioncomprises a card holder ill having transversely spaced side arms 11projecting outwardly from a shaft 12 adapted to be mounted at its endsremovably in journals 3-9 in the side frames 31 of the duplicatorbetween which the cylinders are mounted. Between the side arms 11 extenda cover sheet 13 to which is secured a handle 14 by which the holder maybe manually pivoted. A plate 15 having an aperture 16 defines with coverplate 13 a chamber 17. i

The holder also includes two sets of spaced apart jaws 1d and 19, eachhaving a card receiving slot therebe-tween. The drawings show two cards26 and 21 fitted into these slots and 19 respectively.

In some duplicators, a mounting bar for the ink screen extends acrossthe cylinders parallel to the axes thereof and it is necessary, in suchduplicators, for the apparatus according to this invention to beperiodically moved away cleaning from the cylinders, to allow themounting bar to pass by the apparatus. Although such periodic movementcould be carried out manually, it is preferred that means he provided toensure that it occurs automatically.

This is achieved by utilising a cam surface on a cam 24 driven by a gear25 on the shaft of the lower cylinder to swing the holder away from thecylinders at the appropriate time. The shaft 12 has at one end a lug 22which fits into a slot on a support 23 carried by the appropriatejournal and the said cam surface engages a follower arm 26 carried onthe support 23 thus pivoting shaft 12 and the holder 10.

The position and angles of jaws 1'8 and 19 is such that a piece of cardplaced therebetween is arranged to project therefrom in a plane at anangle of less than 90 to the vertical plane passing through the axes ofthe cylinders of the duplicating machine. As shown, the angles are suchthat the plane of the projecting portion of each of the cards 20 and 21is at an angle of approximately 26 30 minutes to the tangent of eachcylinder at the point of contact of the edge portion with the latter.

In use of the apparatus of the present invention, the silk screen isremoved from the cylinders of the rotary duplicating machine and thelatter are rotated slowly in a clockwise direction, as shown in FIGURE2, and the holder 16} is urged manually or by spring 32 towards the axesof the cylinders, the cards 20 and 21 thus scraping the ink from the twocylinders. The moving of the cleaning edges away from the cylinders iseffected by the operating cam of the duplicating machine acting on lug22. Because such movement occurs as the cylinders are rotating, no linesof ink deposit remain on the cylinders and thus the movement isadvantageously made even in dnp-licators where it is not otherwisenecessary to provide for such movement away from the cylinders.

The chamber 17 is of such a shape that it is particularly convenient touse it as a magazine or container for the strips or cards. A quantity ofstrips or cards are simply flexed and sprung into place in the chamber17, where they are retained in place by their own resilience and byplate 15,

I claim:

In a rotary duplicator comprising side members, two cylinders mountedbetween said side members, surfaces on said cylinders and means forrotating said cylinders about parallel axes and in the same direction,an apparatus for cleaning said cylinder surfaces, such apparatusincluding a holder, a shaft in said holder, journal means on said sidemembers for receiving said shaft for pivota-lly mounting said holder, apair of parallel spaced apart jaws secured to said holder, meansdefining in each said jaw a card receiving slot parallel to said axes, astrip of card held in each said slot and extending beyond one end ofsaid slot and two cleaning edge portions, one on each said card,operatively positioned by said slot defining means to be pressed againstsaid twin cylinders simultaneously at an angle between 20 and 30 to saidcylinder surfaces so as to be in shaving relation therewith, meansdefining a chamber between said jaws said chamber serving as a containerfor unused strips of card, spring means uring said holder towards saidtwin cylinders, support means associated with said journal means, camfollower means connected to said support means, 0. lug on said shaftengaged in said sup-port means and a cam operatively connected to saidrotating means to move periodically said cam follower, support means,lug and holder whereby said cleaning edges are moved from said cylindersurfaces.

References Cited by the Examiner UNITED STATES PATENTS 637,040 11/99Smith 15-25651 1,138,342 5/15 Wood 101-169 1,872,727 8/32 Gestetner101-425 1,906,374 5/33 Gestetner 101-122 2,011,657 8/35 Simon 101-2872,203,273 6/40 Williams 15-25 6.51 2,691,344 10/54 McMu llen 101-425WILLIAM B. PEN N, Primary Examiner.

EUGENE R. CAPOZIO, Examiner.

